Non-healing bone fractures are a significant clinical problem, with few approved medical options. Bone repair of these fractures can be enhanced by the presence of osteoblasts or osteoblast precursors. Preliminary results indicate that stromal cells isolated from extramedullary adipose tissue differentiate into cells which are biochemically and morphologically similar to osteoblasts. The proposed work will determine the bone-forming potential of adipose-derived stromal cells in vivo as well as examine in vitro adipose tissue from a wide range of subjects. Subcutaneous adipose tissue as a donor source of osteoblastic cells would be plentiful, easy to harvest, would engender less secondary morbidity than bone marrow aspiration, and is replenishable. These studies lay the foundation for adipose-derived stromal cells having clinical applications in the repair of bone fractures. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE